Charles River Response Work Shirts Heavyweight Mock Turtleneck is perfect for emergency service professionals, construction, and on-the-job work wear. This shirt is a 80% cotton/20% polyester heavyweight sweatshirt. It has a metal zipper with easy grab rubber pull, rib knit cuffs and hem made of stretchable, spandex reinforced rib knit fabric for added comfort, and a locker loop on the inside below the collar.